- substr: documentation ( source)
- strrev: documentation ( source)
<?php
$str = "racecar";
$pal = "";
for($a=0; $a<strlen($str); $a++)
{
for($z=0; $z<strlen($str); $z++)
$subs = substr($str, $a, $z);
if( $subs == strrev($subs) and strlen($subs) > strlen($pal) ) {
echo $a;
$pal = $subs;
}
}
echo $pal;